1. Field of the Invention
The present invention relates to a ratchet mechanism, and more particularly to a ratchet screw driver and a ratchet wrench.
2. Description of the Prior Art
A typical ratchet mechanism is disclosed in U.S. Pat. No. 2,485,043 to Lofgren and includes a blade spring engaged with a ratchet wheel. However, the blade spring is weak such that the strength of the ratchet mechanism is bad. Another typical ratchet screw driver is disclosed in U.S. Pat. No. 4,777,852 to Herman et al., and includes an actuator that may not be swiftly operated. A further typical ratchet mechanism is disclosed in U.S. Pat. No. 5,053,797 to Huang and includes a plate member or a knob that may not be easily rotated by the users.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional ratchet mechanisms.